Synthesis and deposition of silver nanoparticles on porous titanium substrates for biomedical applications

Abstract

Ti implants are highly biocompatible and allow orderly bone growth but, unfortunately, in the first five years after implantation, 5–10% of them fail due to poor osseointegration and to the presence of bacterial infections in prosthesis. Silver nanoparticles have been described to damage bacterial cell via prolonged release of Ag+ ions as a mode of action when immobilized on a surface. In this work, two routes to synthetize silver nanoparticles have been proposed including, on the one hand, a NaBH4-reduction and, on the other hand, a citrate-reduction combined with a stabilized biodegradable polymer. The deposition of these nanomaterials on porous Ti substrates previously fabricated using the space-holder technique (40 vol% and two size distributions, 100–200 and 355–500 μm) was investigated to aim for the best match. Before the deposition of nanoparticles accomplished by immersion, a silanization treatment of the substrate surface was carried out. After silver nanoparticles were deposited on the porous Ti substrates, microstructural characteristics and antibacterial behavior were evaluated against the proliferation of Staphylococcus aureus on the AgNPs functionalized substrates. Finally, the preliminary qualitative analysis showed the presence of inhibitory halos, being more relevant in the substrates with larger pores.